This invention relates to a tubesheet and tube protector device. More specifically, this invention relates to insulating board and insulated ferrules to be used in a vessel having at least one tube for receiving a fluid extending through the tubesheet.
Conventional tube and tubesheet protector devices include ferrules having round collars connected to shanks. The shanks of the ferrules are inserted into tubes that extend from a tubesheet which covers the inlet of a vessel. To fill the gaps that form between ferrules when the round collars of the ferrules are next to each other and covering part of the tubesheet, the ferrules are installed using a castable or plastic refractory lining that is anchored with stainless steel anchors. By using a castable or plastic refractory lining, the interstices between ferrules are filled so that the entire tubesheet is covered. The shanks of conventional ferrules are wrapped with insulation. However, the round collars of conventional ferrules are not usually wrapped with insulation.
One disadvantage with conventional tubesheet and tube protector devices is that there is insufficient insulation between the collars of the ferrules and the anchors. Thus, anchors and ferrules, especially those in the center of the tubesheet, become damaged or effectively destroyed when the vessel operates at high temperatures. Such devices are especially insufficient for vessels that run with oxygen enriched air because of the high temperatures attained by these vessels.
Another disadvantage with conventional tubesheet protector devices is that ferrules cannot easily be removed and replaced individually because they are installed by being surrounded with a castable or plastic refractory. This is a costly problem because ferrules must be replaced periodically as a result of becoming damaged or destroyed. In addition, damage to the ferrules usually results in severe damage to both the tubes and tubesheet. The net result of this ferrule damage is an expensive re-tubing repair. Still another disadvantage with conventional tube and tubesheet protector devices is that such devices require significant amounts of castable or plastic refractory that must be filled between the interstices formed by the round ferrule collars.
In order to overcome these disadvantages, a tubesheet protector device that provides better insulation than the current conventional devices is needed. This device should be able to withstand high temperatures and preferably should have ferrules that can be replaced individually.